Methods of forming an abrasive slurry and methods for chemical-mechanical polishing

Abstract

Methods of forming a slurry and methods of performing a chemical mechanical polishing (CMP) process utilized in manufacturing semiconductor devices, as described herein, may be performed on semiconductor devices including integrated contact structures with ruthenium (Ru) plug contacts down to a semiconductor substrate. The slurry may be formed by mixing a first abrasive, a second abrasive, and a reactant with a solvent. The first abrasive may include a first particulate including titanium dioxide (TiO2) particles and the second abrasive may include a second particulate that is different from the first particulate. The slurry may be used in a CMP process for removing ruthenium (Ru) materials and dielectric materials from a surface of a workpiece resulting in better WiD loading and planarization of the surface for a flat profile.

What is claimed is: 
     
       1. A method of manufacturing a semiconductor device, the method comprising:
 applying a slurry to a surface of a workpiece, wherein at least one portion of the surface of the workpiece comprises ruthenium; 
 forming a ruthenium oxide layer at the at least one portion of the surface of the workpiece from a chemical reaction between an oxidizer of the slurry and the ruthenium; 
 removing the ruthenium oxide layer and other portions of the surface of the workpiece using an abrasive material of the slurry, wherein the abrasive material comprises a plurality of different particulate materials, at least one of the plurality of different particulate materials comprising titanium dioxide particles, wherein the applying the slurry to the at least one portion of the surface of the workpiece includes applying the slurry to a surface of a ruthenium plug of a middle end of line structure, the surface of the ruthenium plug being coincident the at least one portion of the surface of the workpiece; and 
 producing a non-toxic byproduct from chemical reactions between the ruthenium of the at least one portion of the surface of the workpiece, the titanium dioxide particles of the abrasive material, and the oxidizer. 
 
     
     
       2. The method of  claim 1 , wherein the producing a non-toxic byproduct comprises producing ruthenium hydroxide. 
     
     
       3. The method of  claim 1 , wherein the removing the ruthenium oxide layer and the other portions of the surface of the workpiece includes using a particulate material comprising silicon dioxide as another one of the plurality of particulates of the abrasive material. 
     
     
       4. The method of  claim 1 , wherein the forming a ruthenium oxide layer at the surface of the at least one portion of the surface of the workpiece comprises using hydrogen peroxide as the oxidizer. 
     
     
       5. The method of  claim 1 , wherein at least one of the plurality of different particulate materials comprising aluminum (II) dioxide particles. 
     
     
       6. The method of  claim 1 , wherein the titanium dioxide particles comprise an organic coating. 
     
     
       7. A method of manufacturing a semiconductor device, the method comprising:
 dispensing a chemical mechanical polishing (CMP) slurry on an outer surface of a workpiece, the workpiece including a ruthenium layer with a plurality of ruthenium plugs within an inter-layer dielectric (ILD) layer, the ruthenium layer being located in a middle end of line layer and the dispensing of the CMP slurry is dispensed directly onto the ruthenium layer; 
 using an oxidizer of the CMP slurry to form an oxide layer on a surface of the ruthenium layer; and 
 performing a CMP removal of the oxide layer using a first abrasive of the CMP slurry, wherein the first abrasive includes titanium oxide particles and silicon dioxide particles. 
 
     
     
       8. The method of  claim 7 , wherein the performing the CMP removal of the oxide layer includes removing excess material of the plurality of ruthenium plugs of the ruthenium layer, and removing excess material of the ILD layer from the surface of the workpiece using the CMP slurry, wherein a rate of removal of the oxide layer combined with a rate of removal of the excess material of the ruthenium plugs during the CMP removal is comparable to a rate of removal of the excess material of the ILD layer. 
     
     
       9. The method of  claim 7 , wherein performing the CMP removal of the oxide layer comprises:
 exposing a contact area on an end of one of the plurality of ruthenium plugs at the surface of the workpiece, the exposed contact area being electrically coupled to a finFET device disposed at an opposite end of one of the ruthenium plugs from the exposed contact area. 
 
     
     
       10. The method of  claim 7 , wherein the CMP slurry includes a second abrasive including aluminum (II) dioxide particles. 
     
     
       11. The method of  claim 7 , wherein the oxidizer of the CMP slurry is hydrogen peroxide. 
     
     
       12. The method of  claim 7 , wherein the dispensing the CMP slurry on the outer surface of the workpiece includes dispensing the CMP slurry on the ILD layer. 
     
     
       13. The method of  claim 7 , further comprising:
 producing ruthenium hydroxide as a non-toxic byproduct from chemical reactions between the ruthenium layer, the titanium oxide particles, and the oxidizer. 
 
     
     
       14. A method of forming and using a slurry for chemical mechanical polishing (CMP), the method comprising:
 mixing a first abrasive with a solvent, the first abrasive comprising a first particulate material including titanium dioxide particles; 
 mixing a second abrasive with the solvent, the second abrasive comprising a second particulate material that is different from the first particulate material; 
 mixing a reactant with the solvent, the reactant comprising an oxidizer; and 
 applying the slurry to a surface of a ruthenium plug of a middle end of line structure. 
 
     
     
       15. The method of  claim 14 , wherein the second particulate material comprises silicon dioxide particles. 
     
     
       16. The method of  claim 14 , wherein the second particulate material comprises aluminum oxide particles. 
     
     
       17. The method of  claim 14 , wherein the oxidizer comprises hydrogen peroxide. 
     
     
       18. The method of  claim 14 , wherein the mixing the first abrasive with the solvent comprises providing an organic coating on the titanium dioxide particles. 
     
     
       19. The method of  claim 14 , wherein the mixing the first abrasive with the solvent comprises providing an inorganic coating on the titanium dioxide particles. 
     
     
       20. The method of  claim 14  further comprises mixing a surfactant with the solvent.